Family: Brassicaceae
Genus and Species: Brassica oleracea
Climate
Cauliflower is often referred to as a cole crop. Cauliflower thrives in cool weather and can withstand light frosts. Flavor improves with cooler temperatures because plant cells are working to convert starches to sugars to protect the plant against the cold. The result is a sweet, fresh taste that surpasses that of store-bought heads. Cauliflower does not tolerate wide temperature fluctuations very well.
Soil
Crop rotation is especially important with Cauliflower and other members of the Brassicaceae (previously referred to as the Cruciferae or crucifer) family that includes kale, radish, mustard greens, turnips, and broccoli. 2 - 4 years between plantings of the same family is recommended.
Cauliflower plants will grow in most soils but prefer a pH between 6.4 and 7.4 for optimum growth. Well-drained, loam soils rich in organic matter are ideal for cauliflower plants and especially early plantings of cauliflower.
Spacing
Cauliflower likes room to grow. Plants should have 18" between them with 24"-36" between the rows.
Direct Seeding
A well-prepared seedbed with adequate moisture is a must for direct seeded cauliflower. Sow cauliflower seeds 4 weeks before last spring frost, 1/4" deep, at 18" between plants and 24"-36" between rows.
An alternate method is to plant 2 cauliflower seeds about 1" apart every 18". After cauliflower seedlings emerge and have established, thin to one seedling per couple choosing the strongest.
Seeding For Transplants
Sow cauliflower seed into flats, cells, or soil blocks of soil-less mix. Avoid crowding the seeds. Provide 1-1/2" to 2-1/2" square inches per plant. Ideal temperatures for cauliflower growth are between 45°F at night and 65°F during the day. Begin hardening off the seedlings seven days before transplanting.
Germination
These seeds germinate best in soils around 75°F-85°F.
Germination will take 5-10 days.
Transplanting Into the Garden
Transplant cauliflower plants at 6-8 weeks, 4 weeks before to 2 weeks after the last spring frost. Cauliflower seedlings should be 18" apart with 24"-36" between the rows.
Watering
An even moisture supply is needed for transplants to become established and to produce good heads. Do not over-water in the first 2-3 weeks after transplanting, or 4-5 weeks after direct seeding, especially if club root is suspected. Do not let the seedbed dry out. Such fluctuations in moisture especially when cauliflower reaches the 6 to 7-leaf stage may cause cauliflower to button or form heads prematurely.
Harvesting
Harvest cauliflower heads when they are 5-6 inches in diameter. If harvesting for sale, the cauliflower heads should be white, not discolored, ricey, or blemished. Cauliflower heads are easily damaged so handle with great care. To harvest cauliflower, cut it off the stalk just below the head. If harvesting for sale be sure to include at least 2 leaves for presentation and protection.
Post-Harvest Handling
Cauliflower is highly perishable. The respiration rate of freshly harvested cauliflower is very high and it is therefore necessary to hydro cool cauliflower very soon after harvest and to keep it cool. Hydro cooling is the process of spraying or immersing vegetables in chilled water. Ice water is not recommended as cauliflower heads are easily damaged.
Storage
Cauliflower should be stored at 32°F with a relative humidity of at least 95%. Cauliflower can be held for up to 3 to 4 weeks at 32°F. The storage life for cauliflower is about 2 weeks at 38°F, 7-10 days at 40°F, 5 days at 50°F, and 3 days at 60°F.
Slightly immature, compact heads keep better than more mature ones. Cauliflower is not sensitive to ethylene gases produced by other fruits and vegetables.
Diseases
Club Root, Black Rot, Black Leg, Wirestem, Alternaria Leafspot, and Downy Mildew
Pests
Aphids, Cabbage Loopers, Imported Cabbageworm, Cutworms, Flea Beetles, and Diamond Back Moth
Comments
To get those prized white heads of cauliflower, commercial growers practice a method called 'blanching'. When small white cauliflower heads become visible through the leaves, gather the outer leaves over the head and tie them in place with a string, twine, or large rubber band. This practice will not harm the growth of the head since it is the leaves that conduct photosynthesis.
Cauliflower may form heads early as a result of being stressed. Early head formation results in a small plant with small `curds' often referred to as "buttoning". Cold temperatures, a lack of fertility or water, the use of transplants with poor root growth, rootbound transplants, insect damage, and disease often cause plant stress.
Mulch will help keep the ground cool and moist as well as reduce weed competition.
References
Weekend Gardener, "Cauliflower", Chestnut Software, Inc, http://www.chestnut-sw.com/seeds/vegseed/cauliflr.htm, Accessed 2003-01-04.
Riofrio, M., "Growing Broccoli and Cauliflower in the Home Garden", Ohio State University Extension Fact Sheet, HYG-1605-92, http://ohioline.osu.edu/hyg-fact/1000/1605.html, Accessed 2003-01-04.
Oregon State University, "Cauliflower, Commercial Vegetable Production Guide", Last modified 2002-12-26, Oregon State University, http://oregonstate.edu/Dept/NWREC/cauliflower.html, Accessed 2003-01-04.